Decisions can be made in any number of ways. However, decision making methods that permit consideration of many choices are generally recognized as desirable, at least partly because the ability to consider many choices at least potentially improves the outcome's suitability. Decision making methods that rely on input from multiple sources are also generally recognized as more desirable. The use of multiple sources may effectively increase the amount of information and/or may enable the formation of a consensus view. Unfortunately, as the number of choices and the number of sources increases, the outcome becomes less clear and is often dependent on the particular method employed for decision making. In such circumstances, the decision making method should be chosen with care.
In selecting a decision making method, a system designer may give due consideration to the distinguishing characteristics of different decision making methods. For example, certain decision making methods may require that input sources use a uniform evaluation scale, while others may need only a relative ranking of choices from each source. The uniform scale requirement may undesirably cause a change in a source's measure of the similarity or dissimilarity of different choices relative to other sources, whereas the relative ranking approach nearly eliminates the similarity information altogether.
In many cases, it would be desirable to employ a decision making method that preserves the sources' indications of choice similarity or dissimilarity as the information from the sources is combined to determine an outcome. Such a method would preferably not require that the input sources employ a uniform scale. The literature appears to be devoid of such a decision making method.